DESCRIPTION ( verbatim from the applicant's abstract): Fatty aldehyde conjugates have been limited previously to phospholipids in the form of plasmalogen. We recently found a novel plasmal conjugate linked to galactosyl-sphingosine (psychosine) or to cerebroside through cyclic acetal linkage; these were termed "plasmalopsychosine" (PLPS) and "plasmalocerebroside'' (PLCER), respectively. PLPS induces neurotrophic arid anti-apoptotic effects in PC 12 cells through TrkA activation and prolonged enhancement of mitogen-activated protein kinase. PLPS induces similar effects in neuroblastoma Neuro2a cells independent from the effect of Nerve Growth Factor (NGF). Thus, PLPS mimics NGF effect. We propose to study: (1) structural requirements for neurotrophic and anti-apoptotic effects of PLPS; (2) possible enzymatic conversion of PLCER to PLPS, and tissue distribution pattern of PLPS and PLCER; (3) comparison of neurotrophic effects of PLPS with effects of known neurotrophins in various neuronal cell lines; (4) interactions of PLPS with neurotrophin receptors and "glycosignaling domain" (GSD) which lead to activation of TrkA, p75NTR and other GSD-associated signal transducers; (5) anti-apoptotic activity of PLPS for normal, primary cultured neurons, (6) signal transduction pathways involved in the anti-apoptotic action of PLPS in cultured central and peripheral nervous system neurons, including kinase pathways (ERK, JNK, p38MAPK, AW PBK3, the pS3 tumor suppressor gene, members of the Bc1-2 family (Bc1-2, BC1-XL, Bax, Bad), caspases, [Ca2+]; free radical production and the mitochondrial function. Results of these studies may provide a basis for development of PLPS and its analogues as therapeutic reagents for neurodegenerative diseases and neuronal injury.